INDEX TO VOLUME II. 



459 



ELECTRIC LIGHT. 



effects on vegetation comparable 

 with solar, 252; efficiency, high 

 of, unique in transformation 

 of energy, 208 ; experiments, re- 

 cent, with, at South Foreland, 187 ; 

 Faraday produced, in 1831 by 

 magnetic induction, 198 ; flashes 

 in lighthouses, applicable for pro- 

 ducing, 244 ; flickering of, due to 

 imperfect carbons and varying 

 speed of motor, 190, 200; heat 

 from, sufficient to counteract hoar 

 frost in plant growth, 232 ; Hop- 

 kinson, J.'s, investigations of, 208 : 

 leaves of plants, movement of, to- 

 wards, 228 ; less penetrating in 

 early lighthouse applications, 207 ; 

 penetrating power of, and of oil 

 lamps considered, 192, 207 ; rela- 

 tive penetrating power of, and of 

 oil lamps at Dungeness, La Heve 

 and Lizard, 207 ; power of, esti- i 

 mating, 187 ; powerful, requires 

 careful management, 208 ; more 

 refrangible than oil light, 207 ; 

 scorching effect of uncovered, 229, 

 254 ; subdivision of, 200 ; supply- 

 ing, economically, mode of, 200 ; 

 temperature of, higher than any 

 attainable by combustion, 245 ; 

 unsteadiness of, due to variation 

 in steam pressure, 199 ; upward 

 rays of, intercepted and thrown 

 down, 190 ; workable with any 

 form of prime mover, 245. 

 Electric light and vegetation. Elec- 

 tric light, benefit of, to plants, 

 evidence of, 229 ; chlorophyll pro- 

 duced by, 235 ; coloured glasses, 

 shining through, effect of, 255 ; 

 (j'owjiiiruticf effect of, on plants, 

 acting directly and through glass, 

 254 ; and of combined day and 

 electric light, 230 ; in open air 

 and under glass, 228, 231 ;) in 

 conservatories, improved appear- 

 ance and growth of plants, leaves 



ELECTKIC PYBOMETEB. 



darker, colouring brighter, plants 

 more vigorous, 231, 235, 236, 239 ; 

 at a distance from plants, bene- 

 ficial effects of, 233 ; distance from, 

 at which maximum beneficial 

 effects are produced on plants, 

 233 ; of 1,400 candle-power at 2 

 metres distance from plants equals 

 average daylight in February, 235 ; 

 experiments on flowers and fruit, 

 247 ; experiments on plants, de- 

 scription of and apparatus for, 

 227, 228 ; experiments on plants 

 under influence of, during night, 

 of total darkness, of daylight, and 

 combined day and electric light, 

 228 ; growth of annuals and other 

 plants affected by, 256, 257 ; heat 

 from, counteracts night frost, 232 ; 

 in hothouses with fruit trees and 

 plants, 229 ; inside and outside 

 glass-houses,comparative effects of, 

 253, 254; nitrogenous and other 

 compounds from, do not affect 

 plants under, 230, 235 ; promotes 

 setting and ripening of fruit and 

 produces bloom and aroma, 232, 

 233, 236, 239 ; ripening effected 

 by, 232 ; spectrum of, use of, to 

 determine applicability of rays for 

 different purposes of growth, 237 ; 

 stove heat, ability to sustain in- 

 creased, of plants under, 236 ; in 

 winter to bring plants forward, 

 229. Sec Electro-Horticulture. 



Electric lighting, advancing rapidly 

 at present, 246 ; carrying energy 

 from coal to carbon in lamp, 246. 



Electric motor, lightness and sim- 

 plicity of, compared with portable 

 engine, 260. 



Electric pyrometer, 124 ; applicable 

 for high temperatures, 125 ; 

 change in conductivity of clay of, 

 125 ; checking of, 125 ; (coil of, 

 164 ; with iron case, submitted 

 to trial by Committee of British 



